I just traded my CJ5 for an 89 D250 with the cummins. It's bone stock and needs some love as far as suspension goes. Anyway, I've toyed with the idea of using it for the truck camper but all the stick...
The new rams starting in '94 were 8,600 GVWR. I suspect yours is slightly less. I would guess the truck weighs between 6,000 and 7,000. You could probably get by with an 8 or 9 foot non-slide hardside camper. What you really need is the axle weight ratings. I don't know those off the top of my head. If you stay under your tire and axle ratings with the camper you should be fine.